Phosphonitrogen
磷氮肥
🗣️ 情景例句
Take care on your way back.
回程保重了。
His presence in the room was not noticed.
没有人注意到他在房间里。
riding on its air cushion over a single rail, which it never touches,at speeds up to 300 m.p.h.----the possibilities appear unlimited.
靠气垫在单轨上行驶而不接触轨道，时速可达每小时300英里。气垫船的前途是不可限量的。